nix-darwin: add claude-code and codex via dedicated flakes

Add flake inputs for codex-cli-nix and claude-code-nix with cachix
caching for pre-built binaries, matching the NixOS setup.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

nix-darwin/flake.lock

@@ -8,7 +8,7 @@
           "railbird-secrets",
           "nixpkgs"
         ],
-        "systems": "systems"
+        "systems": "systems_3"
       },
       "locked": {
         "lastModified": 1707830867,
@@ -41,6 +41,48 @@
         "type": "github"
       }
     },
+    "claude-code-nix": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1770168651,
+        "narHash": "sha256-SxzTEu49iaAA/nAT28Rsr4BmjC3eCkiaM4/ZYBVhhNQ=",
+        "owner": "sadjow",
+        "repo": "claude-code-nix",
+        "rev": "f256f48c037a6e54afa332795328f753f2fafbaf",
+        "type": "github"
+      },
+      "original": {
+        "owner": "sadjow",
+        "repo": "claude-code-nix",
+        "type": "github"
+      }
+    },
+    "codex-cli-nix": {
+      "inputs": {
+        "flake-utils": "flake-utils_2",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1770232831,
+        "narHash": "sha256-C5e2wjd//pLJA1LqSYc/y9aZkM8wmZo/BAuzhZDuyFE=",
+        "owner": "sadjow",
+        "repo": "codex-cli-nix",
+        "rev": "64805eb1d1afffcbbcef0ffc053295f0065cd51d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "sadjow",
+        "repo": "codex-cli-nix",
+        "type": "github"
+      }
+    },
     "darwin": {
       "inputs": {
         "nixpkgs": [
@@ -65,9 +107,45 @@
       }
     },
     "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "flake-utils_2": {
       "inputs": {
         "systems": "systems_2"
       },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "flake-utils_3": {
+      "inputs": {
+        "systems": "systems_4"
+      },
       "locked": {
         "lastModified": 1709126324,
         "narHash": "sha256-q6EQdSeUZOG26WelxqkmR7kArjgWCdw5sfJVHPH/7j8=",
@@ -229,7 +307,7 @@
     "railbird-secrets": {
       "inputs": {
         "agenix": "agenix",
-        "flake-utils": "flake-utils",
+        "flake-utils": "flake-utils_3",
         "nixpkgs": "nixpkgs_2"
       },
       "locked": {
@@ -248,6 +326,8 @@
     },
     "root": {
       "inputs": {
+        "claude-code-nix": "claude-code-nix",
+        "codex-cli-nix": "codex-cli-nix",
         "home-manager": "home-manager",
         "homebrew-cask": "homebrew-cask",
         "homebrew-core": "homebrew-core",
@@ -286,6 +366,36 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "systems_3": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "systems_4": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",

nix-darwin/flake.nix

@@ -21,6 +21,16 @@
     };
     home-manager.url = "github:nix-community/home-manager";
     home-manager.inputs.nixpkgs.follows = "nixpkgs";
+
+    codex-cli-nix = {
+      url = "github:sadjow/codex-cli-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
+    claude-code-nix = {
+      url = "github:sadjow/claude-code-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs = inputs@{ self, nix-darwin, nixpkgs, home-manager, ... }:
@@ -112,7 +122,14 @@
         };
       };
 
-      nixpkgs.overlays = [(import ../nixos/overlay.nix)];
+      nixpkgs.overlays = [
+        (import ../nixos/overlay.nix)
+        # Use codex and claude-code from dedicated flakes with cachix
+        (final: prev: {
+          codex = inputs.codex-cli-nix.packages.${prev.stdenv.hostPlatform.system}.default;
+          claude-code = inputs.claude-code-nix.packages.${prev.stdenv.hostPlatform.system}.default;
+        })
+      ];
       environment.systemPackages = with pkgs; [
         #python-with-my-packages
         emacs
@@ -126,7 +143,8 @@
         nodejs
         ripgrep
         slack
-	      claude-code
+        claude-code
+        codex
         typescript
         vim
         yarn
@@ -141,7 +159,18 @@
       programs.direnv.enable = true;
 
       # Necessary for using flakes on this system.
-      nix.settings.experimental-features = "nix-command flakes";
+      nix.settings = {
+        experimental-features = "nix-command flakes";
+        substituters = [
+          "https://cache.nixos.org"
+          "https://codex-cli.cachix.org"
+          "https://claude-code.cachix.org"
+        ];
+        trusted-public-keys = [
+          "codex-cli.cachix.org-1:1Br3H1hHoRYG22n//cGKJOk3cQXgYobUel6O8DgSing="
+          "claude-code.cachix.org-1:YeXf2aNu7UTX8Vwrze0za1WEDS+4DuI2kVeWEE4fsRk="
+        ];
+      };
 
 
       # Set Git commit hash for darwin-version.